The employee apparently cut her finger on a meat slicer and left her station without immediately telling anyone, said Steve Hall, the environmental health director for the Jackson County health department. Her co-workers continued filling orders until they found out what had happened, he said.

John Gray, a spokesman for Atlanta-based Arby's, released a statement Wednesday apologizing for what he described as an isolated and "unfortunate incident." He said Arby's is still investigating, but has determined that the Jackson workers shut down food production as soon as they found out what happened and thoroughly cleaned and sanitized the restaurant.

The injured employee was treated at a hospital. Mr. Gray said the franchise has fully cooperated with health officials and was given the approval to remain open.

Ryan's mother, Jamie Vail, was incredulous. She and her friend, Joe Wheaton, had taken Ryan and his 11-year-old brother to the Arby's drive-thru and she told the Citizen Patriot she thought her son was joking when he exclaimed he had found a piece of a finger in his sandwich.

"Somebody loses a finger, and you keep sending food out the window? I can't believe that," said Ms. Vail. She and Mr. Wheaton said the severed section was about an eighth to a quarter-inch thick and at least one inch long.

Vail said she called 911 and met police at a local health center, where her son's blood was drawn and he was prescribed some medication.

Ryan said he is feeling fine. Vail told the paper she has been in touch with a lawyer, but hasn't decided whether to pursue the matter.

There have been a number of incidents in recent years in which a restaurant worker's accidentally severed flesh found its way into someone's food.

In 2006, a diner at a TGI Friday's in Indiana found part of a kitchen worker's finger on his hamburger. The year before that, a North Carolina man bit into what he thought was candy in his frozen yogurt only to find it, too, belonged to a worker who had had an accident with a food-processing machine.

There have also been hoaxes, including one perpetrated by a Nevada woman and her husband, who claimed in 2005 that she bit into a severed finger in a bowl of chili she bought at a Wendy's in San Jose, Calif. Both received lengthy prison terms after admitting it was a hoax. Wendy's said the bad publicity cost it millions of dollars in sales.